By George Mullen

 

Desert tortoiseMost traditional methods for recovering gold from gravels require an ample supply of water. However, an old prospector’s adage has it that gold is where you find it. In the southwest, the “where” is all too frequently situated miles from even a trickle of water. Dry-washing of gold-bearing soil or gravel provides an effective solution to this dilemma.

Click here for a more thorough explanation of dry-washing techniques.

The Spaniards used a scheme similar to the winnowing of wheat from chaff and straw. Two men would grab the comers of a blanket, upon which a small quantity of classified gold-bearing material had been placed, and they repeatedly would toss it upward into the air. The wind would blow away the lighter fraction, and any gold and black sands, which are heavier, would fall back onto the blanket. Wool blankets worked best, because the static electrical charge generated by the wool tended to attract fine-sized gold on the blanket’s surface.

The modem prospector uses an efficient tool called a dry-washer to extract the ever-elusive gold particles from screened gravels or other material. Dry-washers can range in size and complexity from hand-shovel-fed models, to large machines serviced by wheeled or tracked front-end loaders.

All dry-washing machines require a low-pressure, high-volume source of air. At the low-cost end, this can be provided by a bellows which is linked to a hand-operated crank or motor-driven fly wheel. At the higher-cost end, the air source is typically provided by a gasoline engine-driven blower. The remaining components of a dry-washer combine to construct a sloped classification screen (or “grizzly”), which routes fine-sized material to a pneumatic sluice box, where a mechanically-modulated flow of air accomplishes the separation of gold from the lighter-weight material which contains no value.

Dry-washing for goldA dry-washer for small-scale prospecting might consist of a rectangular screen with 1/2 inch openings over a sloped trough. The screened material would pass from the lower-end of the trough to the head-end of a sloped riffle tray consisting of cotton fabric stretched over an inner frame. The tray includes sides to contain the flowing material, and its surface is interrupted by five crosswise riffles. Under the tray is a hollow box and the mechanism which modulates air flow through the tray at a rate of about 200 puffs per minute. The rate of air flow is designed to be sufficient to lift lighter material over the riffles, while the gold remains trapped. When everything is working right, the flow of material through the riffle tray resembles water flowing through a conventional sluice box.

My dry-washer was built from a plan published by Carl Fischer. It is mostly constructed of wood and is extremely portable. A small gasoline engine drives the air box via a belt and pulley speed reducer, producing the required 200 puffs of air per minute. The end result is an efficient separator which saves even the finest particles of gold. I have checked the tailings on numerous occasions and have yet to find any significant amount gold in them.

Prospecting for gold in the desert uses techniques similar to those that are used to locate placer gold on flowing streams or within old stream channels. You want to sample dry-washes on pediments to mountains, feeder-canyons in the mountains and ancient streambeds.

Another old prospector’s adage suggests that one should look for gold where it has been found before. This is still sound advice!

Very fine gold is abundant at many sites in the northwest, and the usual methods of final gold recovery do not always work very well. I have found that the screening and drying of dredge or high-banker concentrates, and then running them through my dry-washer, really works well. I use a metal detector to monitor both the feed and the tailings.

After processing pay-dirt material for about an hour, I suggest it is usually a good idea to clean-up the riffles to check your recovery. I use a plastic gold pan and small wash tub for the final clean-up and have operated all day on just a few gallons of water.

My wife, some friends and I operate suction dredges and high-bankers on the extensive New 49’er properties near Happy Camp, California during the summer months, where there is always an abundance of water. Our dry-washer allows us to remain active during the winter, usually around Quartzsite, Arizona. These gold prospecting and mining activities provide enjoyable activity, along with an extra source of income when we need it.

 

By Sam Radding

How to Determine what “Good Gold” Means to You

 

Damp soilThe meaning of “Good Gold” is a matter of perspective and experience. This phrase is generally used in terms of quantity and ease of extraction. A couple of old-timers, sitting around the fire talking gold, will often have enough shared-experiences to know what the other means by “good.”

“This soil is very damp.”

The captivating nature of gold brings out different emotional responses from each of us.

The problem lies in the fact that just about every novice miner starts with little or no knowledge of the realities in the activity of gold prospecting. Our story may serve to shed some light on what to expect from your own first few mining trips.

Jean and I live in San Diego. To start with, our part of the country is very dry. So, a lot of the gold hunting is accomplished using a dry-washer. There are a few placer areas within an hour’s drive of our house, but they have very limited access and the gold tends to be pretty sparse. We tried some gold panning and found a few specks of gold; but from what we could determine from the local prospector’s club and friends, the Pot Holes would be a better-than-average place to start. This area is about a three-hour drive from San Diego, and is near Yuma, Arizona, but still in California.

Dry-washerBuilding a workable dry-washer would be a snap. I have always been good at figuring out how machines work and how they should be constructed. Ten minutes with a friends’ bellows dry-washer was enough to get me started on our own machine. A few days later, we were packed and driving to the desert with our newly-built dry-washer and an old 3-horsepower Briggs and Stratton engine. I just had to test my new creation. When it comes to gold, to me, now is always better than later.

Our maps were good, so we had no trouble finding the bridge across the American Canal along with the road to the open recreational mining area just southwest of the old 3 C’s mine. The road in had a few rough spots, but nothing that our little Vega station wagon (with three-inch ground clearance) could not make. By the way, this location still remains open to anyone; and to this day, it is still productive.

The big problem was where to start. Book gold is a lot different than real gold. The books we read were small and the maps and locations where gold would be trapped seemed fairly straight forward. The Pot Holes was huge; and of course, we wanted to work in the best spots. We wanted to find some “Good Gold!” I had read several articles about the importance of prospecting and sampling before you decide to invest the bulk of your resources to any particular area.

Jean and I do argue on occasion; and as it turned out, picking-out our first dry-washing spot was a perfect time to disagree (Thirteen years later, so we can minimize disagreements, we now have two of almost all the equipment we use.). After about fifteen minutes, we jointly settled on a small wash. There were a few tree roots and some exposed bedrock to work. This wash was about a hundred yards from where we parked the car. After packing our gear to the site, we set the engine and dry-washer in place; with the engine upwind to keep it free from the dust generated by our dry-washer. Then, with the dry-washer delivering about 90 beats per minute (possibly a little fast for the conditions we were working), we proceeded to dig and feed gravel to the dry-washer for about a half-hour. We had brought along some water for the purpose, so we practically ran back to the Vega to pan our concentrates. Much to our surprise, we had almost no gold. We just had some small specks.

Our next spot was just down from where our first little wash emptied into a slightly larger dry-wash. The opposite bank looked good to me. There was some exposed bedrock, and the overburden was only about a foot deep. The digging was very easy; and after an hour, we decided once again to check our progress. I was impressed this time. There were lots of little flakes. Jean was not so favorably-disposed. It still looked like specks to her; and after a short time, it began to look that way to me, too. Another move seemed to be in order. We spent the next two and a half days moving from place to place, from specks of gold, to specks of gold.

Jean was getting a little frazzled, and I was getting more and more frustrated. I wanted to go back to the place that impressed me on the first day. The bank on the small wash gave up about 1 pennyweight (about l/20th of an ounce) of gold in an hour, even if they were only small specks. To us, it did not look like very much gold and I didn’t know if it was good or bad; but that spot seemed far better than the other places we had dry-washed during the past few days. I really wanted to go back.

Jean went back to camp to make lunch and I picked up the dry-washer, engine and the pick and shovel and started off to my spot. After about ten steps, I heard a rumble. My first thought was that it couldn’t be thunder, not here. A quick glance over to the west set me straight. Over my head, it was sunny and blue. A few miles away, it was dark, very dark. Even I knew that it was impossible to dry-wash in wet material.

The thunderstorm might move the other direction. But at worst, I would have a little time to work. I hobbled to my spot, carrying over 75 pounds of gear and equipment, and quickly set up the dry-washer and engine. If it was going to rain, then I was going to shovel as much material through the dry-washer as it would take. I worked hard as the storm crept closer. The first big drops of rain arrived about an hour later. Ten minutes after that, our dry-washing was finished for this trip. I had kept the riffle tray dry as I had been told. Dust and moisture in the riffle tray cloth create cement, and that combination will not pass air. No air means no gold; which in turn, means stretching a new cloth for the dry-washer.

Everything else was wet. We panned-out my concentrates, and our total gold for the trip filled a two-pennyweight vial and half of another. We had over 3 pennyweights, most which came in two hours of dry-washing at my spot. It still looked like specks, but there sure were a lot of them. Our problem was that we had no yardstick by which to judge “Good Gold.” Back home, we told some mining friends about our spot in some detail and about how we had done. We thought there might be some more gold there and we were going back in a couple of weeks, after things had dried out a bit. Our more-experienced friends were impressed when we showed them our gold from our very first prospecting trip.

If you have never dry-washed, you must remember that any moisture in the pay-dirt will make any dry-washer less efficient. An easy way to check for water-content is to squeeze a handful of your pay-dirt into a ball. Then open your hand. If the ball falls apart, the material is very dry. If the ball breaks into several smaller sections and tends to crumble, you are working with slightly-damp material. Most dry-washers will run this material, but the efficiency will be diminished somewhat. If the ball stays intact or breaks into two or three parts, the pay-dirt must be dried before running through the dry-washer. On a good day, most dry-washers will lose between 10% and 20% of the finer-sized gold which remains trapped in small dirt balls. They pass right through the machine!

When we got back to our spot three weeks later, the site had already been cleaned out. We did get a little more gold, but we later found out that a few of our more-experienced friends went in there before us and recovered about two ounces of gold during our absence. From that time forward, both Jean and I had a little better understanding of what the term “Good Gold” means!

To this day, I still have a hard time keeping my mouth shut when it comes to where we are working and what we are finding. Most gold prospectors that we meet find this an endearing, if not a foolish, trait to have. I am getting the idea that when it comes to gold, you have to be careful how you conduct your business affairs!

If you are just starting out, whether you are working on a river, stream or in the desert, or whether you are using a dry-washer, sluicing system or four-inch dredge, recovering a pennyweight of gold an hour is making “Good Gold.” Two-to-five pennyweights in a day’s work is fairly good for small equipment. I personally average a little over two pennyweights per day when I am sniping (finding gold with hand tools and a face mask) on my favorite rivers in the Mother Lode area.

Over the years, I have built over a hundred dry-washers, both the bellows and constant-air types. I have written books on the home-construction of small-scale mining equipment. Jean and I spend most of every summer looking for gold. More gold is always better than less gold; but to me, I feel I have done well if my final clean-up produces over two pennyweights in a day. This is my personal yardstick for how I am doing. The amount of gold we find is important, but we are also enjoying what we are doing.

Here is where you can buy a sample of natural gold.

 

 

BY SAM LONG

 

Dry-washing, in many ways, puts me in mind of eating at a Chinese restaurant with chopsticks. It’s fun to try; but you can’t move material from one place to another very fast, even if you’re good at it. That’s why it’s so important to pick out an area with a theoretically high concentration of gold. Of course, down here in Arizona, you’ve got about as much chance of finding an area like that as a one legged man’s got at winning a kicking contest!

That’s not to say you shouldn’t try. I always do so with this theory in mind: Billions of years ago, when God was putting tons of gold in Alaska, South America, Russia, Australia, the Yukon, and even California, he accidentally spilled a couple of pounds over Arizona. I always think of that after I’ve worked through a pile of rocks and sand big enough to shade an elephant, and not come up with enough gold to fill a tooth. All the expert mining techniques in the world won’t come up with a speck of gold where there’s none to begin with. So, the place to start is history.

I know you’ve read it a thousand times. Now you can say you’ve read it over a thousand times: It’s usually better to begin your search for gold in an area that has produced it in the past. The more the better.

From that point, go to maps. Study them religiously. I take my topographical maps to an office supply that has an enlarging copier. I have the section I’m interested in blown up two or three times. This really helps in seeing all the side washes, forks, bends, and places of slowing water that are the obvious holding spots for gold.

Now, you’re ready to hike to these areas. Of course, on your way to and from these spots, keep your eye open for any likely looking area you might have overlooked on your map. There are a zillion of them, so you’ve got to learn to be very selective.

Remember, you want to shovel rocks, sand, and gold through your dry-washer, not just rocks and sand. It doesn’t matter to your shovel. It doesn’t matter to your neighbor. It only matters to you. Take your best shot before you ever crank up your machine, and you won’t have to deal with the disappointment of getting skunked.

And, just how do you do this? Sampling. That’s right— sample, sample, sample. If you’re diligent about it, and do it correctly, when you finally start dry-washing, your question won’t be will I find gold? It will be how much will I find?

Starting up your dry-washer in a likely-looking spot without sampling, makes about as much sense as a dog barking at a knothole. Sure, sampling is a lot of extra work and it takes time. But, when it’s all said and done, you’ll end up with some gold along with the new blisters–instead of a sour attitude and the new blisters.

This isn’t to say you can’t set up anywhere and get some color. But to my way of thinking, that would be pure luck; and I haven’t experienced enough of that to feel qualified to write about it. If you have, and can make it work time and time again, I’d sure be willing to learn.

So, here we are in a gold producing area, walking up a wash that had some likely-looking gold-holding spots on our map. How do we sample? Well, as with most things, there is more than one way to skin a cat. I use a Goldspear. It’s proven itself to me to be an accurate, time saving, prospecting tool. I know lots of folks don’t think much of them, but usually they haven’t ever owned one, or don’t understand how to use them to their advantage. Granted, they’re not some super tool that can automatically find gold. But used correctly, they can sure save you a lot of needless digging. And, at the price of shovels these days, you don’t want to wear out any more than necessary.

For now though, I’ll skip the use of the spear and explain a few points of how I sample without one. Again, this isn’t the only way to sample or dry-wash, but it works for me. Adapt it to your own personality and tools, as you see fit. In my pack, my basic tools are: Two pans, a small kitchen sieve; and, because we’re prospecting dry washes, a wide-mouth plastic gallon jar of water. Needless to say, never go anywhere without your rock pick.

With these basic tools, slowly work your way up the wash, visually sampling as you go. In your mind’s eye, continually look for the places gold is likely to accumulate. The more of these types of places you can recognize, the more success you’ll have in sampling.

Likely gold-holding areas would be the inside of sharp bends; areas where the wash levels and widens, indicating slowing water; areas of red and blue clay; pockets of iron pebbles, which show the water’s inability to carry heavier minerals; or a zone of magnetite, hematite or quartz. All these are good visual indicators that gold will likely be present.

After finding a place containing as many positive indicators as possible, roll over the biggest boulder you can in that area; and using one pan to hold the water, screen some material from under the boulder into the other pan and go to work. If you’ve done your homework right, this should yield you a few colors. Jot down how many on your map at the place where you found them. If more than just a few colors materialize, try a couple more pans before moving on. Continue in this manner for the rest of the day. You should have a few different areas that are somewhat better than the others.

Now that you’ve picked a good spot to work, and packed in all your equipment, the last important point is the speed at which you run the material through your dry-washer. It’s a big temptation to drop your riffle board too low so you can process material faster. But by doing this, you’ll lose a lot of finer-sized gold. As you either know, or will soon find out, most gold in the dry washes is very small. Unless you keep your riffle board only slightly lower than level, a good portion of the fine gold won’t have time to settle. It will end up going over the end instead. You can’t feed any more material in than is going out, so be careful not to overfeed the hopper. Otherwise, you’ll end up with gold in your tailing pile. Nothing will make you feel ankle high to a frog in a post hole quicker than your neighbor coming by, to run his Goldspear through your tailing pile, and getting enough beeps to make a liar out of you, when you tell him you were planning to run it through again a second time anyway.

The biggest hindrances to running your machine are laziness and rain. If you’re the type who does more spitting on the handle than shoveling, you’ll probably welcome the rain. If not, the folks around you will surely think you were raised on sour milk. It takes the fun out of dry-washing when you just get going good, then it rains and stops your operation. That’s what happened to us this winter. With my Keene dry-washer, I could work wetter dirt than everyone else because it blows hot air. But after the fourth cloudburst, it was even too wet for me. We switched it to a re-circulating water system and kept going.

So, if you pick the right spot and don’t push your machine, you’ll get some good gold. It might not be the most gold you’ll ever get in a day, but that desert-gold is some of the prettiest you’ll ever find. Since gold is more ornamental than useful anyway, you ought to be happier than a fly in a raisin pie

 
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By Dave McCracken

Always set up a dry-washer downwind of where you are working!

Dave Mack

 

Deserts consist of huge deposits of sedimentary material which have been affected by ancient ocean tides, ancient rivers, glaciers, floods, gully washers and windstorms. They are literally a gold mine of placer deposits.

There is also an enormous amount of gold-bearing mountainous dry placer ground which has remained relatively untouched by large-scale gold mining activity because of the scarcity of water required in those locations to support wet recovery methods.

Generally speaking, dry methods of gold recovery are not as effective or as fast as wet recovery methods. Yet, dry methods do work well enough that they can produce gold well if the ground is rich enough. Recent developments in dry washing equipment have made it possible for a one or two-man operation to work larger volumes of dry placer ground without water, and obtain good results in gold recovery.

Dry processing recovery systems generally use air flows to do the same job that water does in wet recovery systems. Under controlled conditions, air flows and mechanical motion and vibration can be made to effectively get rid of lighter, worthless materials. This causes a concentration of heavier materials similar to what occurs in wet processing.

SETTING UP TO WORK AN AREA

Sometimes a road can be bulldozed to your spot. Sometimes you can drive right in with a 2 or 4-wheel drive truck. In these situations, you might consider screening pay-dirt into the back of a truck and hauling it to a wash plant to be processed elsewhere. Actually, this is just slightly more difficult than shoveling directly into a wash plant. The hardest part is breaking the material away from the streambed and classifying it. It takes a little more time to haul the material to the wash plant, but that depends upon the distance and the condition of the road. It is also more difficult to shovel up into a truck. Some small operations use a portable conveyor belt to lift the material into their truck. Feeding the material from a truck into a wash plant is not as difficult, because it is usually down hill. An average one or two-person team should be able to move the equivalent of a pickup-sized load of screened pay-dirt and process it through a wash plant at another location in the period of a full day’s work-perhaps even two truckloads, depending upon the distances involved. If the material is paying well, they could do well at it, too.

DRY-WASHING PLANTS

If conditions do not allow you to truck the pay-dirt to a nearby water site to be processed by wet methods, you will have to consider processing the rich material by dry-production methods.

While dry-panning and winnowing do work, and have been broadly used as a means of production during the past, they are not normally as effective as some of the modern dry-washing plants which are available on today’s market.

Dry-washing machines use an air blowing fan or bellows-type device to blow a controlled amount of air-flow up through the dry material that is being processed. Air flows help blow off the lighter materials and allow the heaviest particles and gold to collect.

Dry-washing plants are available which can either be operated by hand or by lightweight engine and air-fan assemblies.

“Non-motorized dry-washing unit”

A hand-operated dry washing plant usually includes its own classification screen as part of the unit. Raw material can be shoveled directly onto it. The bellows air-blower is usually operated by turning a hand crank, which is often conveniently located so that one person can both shovel and alternately work the bellows at the same time. Under ideal conditions, two people working together can process up to a half-ton of gravel per hour by taking turns, one person shoveling while the other works the bellows.

Some units also have a 12-volt electric conversion kit to allow you the option to either hand-crank in the field or connect to a 12-volt battery for automatic bellows operation.

Various gasoline motor-driven dry concentrating units are available on the market which utilize static electricity and high-frequency vibration to help with gold recovery. Most commonly, there is a high-powered air-fan which pumps air through a discharge hose into the concentrator’s recovery system. The air currents which pass through the recovery system are adjustable so that the proper amount of flow of lighter materials through the recovery system can be obtained-similar to a sluice box in wet-processing. The purpose of the steady airflow is to “float off” the lighter materials through the box. Heavier materials like gold will have too much weight to be swept through the recovery system by the flow of air.

The bottom matting in this type of concentrator is usually made up of a specialized material which creates an electrostatic charge as high velocity air is passed through it from the air discharge hose. Fine pieces of gold, while not magnetic, do tend to be attracted to surfaces which have been electrostatically-charged, similar to the way iron particles are attracted to a magnet. So the bottom matting in these concentrators often attract fine particles gold to itself and tends to hold them there.

Some motorized dry concentrators also use a high-frequency vibrating device to keep the entire recovery system in continuous vibration while in operation. The way to get gold particles to settle quickly down through other lighter materials is to put the materials into a state of suspension. The vibrating device on this concentrator helps fine particles of gold work their way down through lighter materials that are being suspended by air-flows.

Here follows an excellent video demonstration which shows exactly how motorized dry concentrators work:

A motorized dry-washing machine is excellent for the production demands of a one or two-person operation. Under ideal conditions, it is able to process up to about a ton of raw material per hour, which is the equivalent of what a medium-sized wet sluicing operation can produce. This is as much or more than one or two people can usually shovel at production speed when working compacted streambed material. Most motorized dry-washers do their own screening of materials and almost everything else automatically. This leaves the operator free to produce at his or her own comfortable speed.

Total weight of the average motorized dry-washer is about 75 pounds, but the units do break down into separate pieces which can usually be carried around by a single person. So the electrostatic concentrator can be carried to a hot spot if it is worth a few trips to do so. They usually get about 3 hours to the gallon of gasoline.

SETTING UP A DRY-WASHER

There is no fixed formula for setting up the proper air flows and downward pitch on the recovery system of a dry-washer. A lot depends upon the nature of the material that you are processing, how heavy it is, whether or not the material is angular or water-worn and the purity (specific gravity) and size of the gold being recovered. Each of these variables is likely to affect how you must set your recovery system in each different place that it is operated.

The main thing to remember is that the machine needs to separate the gold from the lighter, valueless materials. If you only have a small amount of air-flow running through your dry-washer, then you will need more pitch on the recovery system-and you may need to feed the material slower. Too much air flow can also be a problem. Normally, you would compensate by adjusting to a lesser pitch on the riffle board.

Watch how the material flows over the riffle board. You should see the dirt rise up in an orderly fashion and flow over top of each riffle. It looks an awful lot like water. It is best to keep a steady feed of material going through a dry-washer at all times. The riffles should be filled about half to three-quarters, with a steady flow moving from one riffle to the next. The material in the riffles should have a fluid look to them; they should not be packed solid.

This following very important video sequence demonstrates how to set up and operate a motorized dry-washer, and it shows exactly what you should look for while making flow adjustments to obtain optimum gold recovery:

It is a good idea to shovel lower-grade material into your dry-washer while adjusting for the proper air flows and pitch. Once set, you can shovel in the pay-dirt.

One thing about dry-washing is that because it is generally slower than wet methods, the pay-dirt must have more gold. High-grade areas in the deserts certainly do exist! This is all the more reason to make sure your recovery system is set properly before processing pay-dirt. Chances are that you will not see any gold that might be discharged into the tailing pile through a dry-washer recovery system.

Another thing about setting up a dry-washing production program is that you always set up a dry-washer downwind of where you are working!

Once gold falls into the dead air space within the riffles, it will usually stay there. The air-flows are generally not strong enough to push gold out of there. There is a limit to this, however. Just like a water recovery system, a dry-washer will concentrate the heaviest materials which it processes. After some time, the heavier concentrates may require stronger air flows or a steeper pitch to keep them in suspension. At this point, it is probably time to clean up the recovery system and start all over again. If you are keeping a close eye on your recovery system, you can see when it is time to clean up. The fluidity of the material inside the riffles becomes more concentrated and slows down.

DRY-WASHING AND CLAY-LIKE MATERIALS

Material to be processed must be thoroughly dry to get the best results out of any dry-washing plant. Sometimes you will run into moist clays when out in the dry regions-just like you do in the wet streambed areas. It is also possible to find a pay-layer associated with the clay. Clays make dry-washing procedure more difficult, because they must be thoroughly dried out and broken up before being processed effectively by dry methods.

Sometimes this means the material needs to be set out in the sun to dry for a full day or more before anything further can be done with it. Sometimes it is necessary to dig clay a couple of days ahead of the processing stage. You can alternate spending a day digging and laying out material to dry, and then a day processing dried material. Sometimes, the dried clay can harden into clumps, which then must be broken down into dust and sand before you can recover the gold out of it. When necessary, all of these requirements require more time and energy. But if a good pay-streak is involved, you will find yourself doing whatever is necessary to recover the gold out of it.

It may be necessary to use rock-crushing machinery to break up hardened clay-like material and crush it down on any kind of a production -scale.

The clean-up of concentrates from a dry-washing plant is accomplished best by wet-processing methods. Usually, if you have room-enough to haul around a dry-washing plant in your vehicle, you will also have room for enough water to pan down your final concentrates, too. The following video sequence demonstrates how and when to perform a final clean-up during dry-washing:

If water is not available to you out in the field, the clean-up of your dry concentrates can sometimes be accomplished quite effectively by running them through your dry-washing plant several times. Final cleanup procedures can then be done to separate the gold from the last bit of remaining valueless material.

DESERT PLACER GEOLOGY

The chances of finding a hotspot out in the desert, or in some other dry region, are probably just as good or as your chances of finding a hotspot in the watersheds of the gold-bearing mountainous areas. These chances are pretty good, providing that you are willing to spend the time, study and work that is necessary to implement a good sampling plan.

Probably your best bet is to start off with a “Where to Find Gold” book and study the geological reports which apply to the area(s) of your interest. There has been some small-scale mining activity out in the dry regions. Much of it was lode mining, but some placer activity took place, as well. A good portion of prior activity is recorded information today. It can be of great value to you to know where gold has already been found. It is almost a sure thing that the areas which were once worked for gold at a profit were not entirely worked out. They might be worked again with today’s modern equipment at a profit. Any area which has once proven to pay in gold values is a good generalized area to do some sampling activity to see if additional pay-dirt can be found.

The desert areas were pretty-much left alone by the large-scale mining activities of earlier times because of the accessibility problem. Often, during earlier times, there was not enough water to sustain life, much less to process gold-bearing material.

But desert prospector should not limit him or herself to only the once-proven areas. Most of the desert regions have gone pretty-much untouched by past (effective) sampling activity because of accessibility problems, lack of water, and not having adequate equipment to do the job up until recent years. So the desert prospector has access to a lot of ground, and there are not that many competitors to worry about.

A single large rain or wind storm can change the entire face of the desert in just a few hours. There is very little undergrowth in these areas to prevent a good-sized rain storm from causing an incredible amount of erosion. And so you hear all the old-timers’ stories of finding bonanza-sized gold deposits, marking their position, going out after tools and supplies, and then returning to find the desert entirely changed and the bonanza apparently gone. Undoubtedly, some of these treasure stories are true. After all, many of those old-timers had gold to go along with their stories. Many of them spent the rest of their lives looking for their “lost gold mine.”

All of the placer geology concerning wet areas also applies to desert placer deposits (most which were developed during wet storm events). The same remains true of eluvial deposits-which is the gold that has weathered from a lode and been swept some distance away by the forces of nature. Eluvial deposits in the deserts (called “Bajada placers”) tend to spread out much more widely, and in different directions. This is because they are usually not eroding down the side of a steep mountainous slope. Therefore, they are sometimes a little more difficult to trace back to their original lodes. But it can be done. The answer is to do lots of sampling.

History has shown that one of the best locations to look for gold is where the hills meet the desert and fan out. This is where the water slows down during flood storms and drops gold in the gullies and washes. There also are likely to be more gold traps further up the hillside.

When doing generalized sampling in the desert, concentrate much of your activities in the washed-out areas, where natural erosion has cut through the sediments and created a concentration of heavier materials. Dry-washes, dry streambeds and canyons are good for this. Get an eye for the terrain, looking over the high points and the low points to get an idea of where the water flows during large flood storms. Areas where the greatest amount of erosion has taken place are areas where the highest concentration of gold values might be found. Remember that we are looking at many thousands of years of erosive impacts.

Bedrock will be exposed in some low areas, as in canyons and dry washes. These are ideal places for you to get into the lowest stratum of material-where the largest concentrations of gold values are often found. Large and small canyons have been formed by many years of erosion and are likely spots to find paying quantities of gold.

Caliche is cement-like false bedrock which is commonly found in desert placer areas.(photo USGS)

The desert and dry areas also commonly have a “false bedrock” layer specifically called “caliche.” Sometimes (often), this caliche layer is only a foot or two thick. In some areas, gold is concentrated along the caliche, just like on top of bedrock.

After a storm in the desert, in some places you can find small pockets of gold in the gravel traps, under rocks and under boulders which rest on top of the caliche. Sometimes the gold is pounded directly into the caliche and needs to be removed with a pick or crevice tool. Caliche layers which are close to the surface allow small-scale dry-washing operations to be economically feasible, because of the lesser amount of gravel and material which needs to be shoveled off the gold deposits.

Streambed material can be recognized by the smooth water-worn rocks. Anywhere in gold country, where streambed material is present, is a prime area to be doing some preliminary sampling. Such material indicates that it has been exposed to a substantial amount of running water. This means concentrating activity took place with those same materials. It is possible that the material was once washed out of an ancient river.

However, gravel and material does not need to be water-worn to carry gold in the desert areas. Rough and angular gravel, which has not been greatly affected by water, also sometimes carries gold in volume amounts. Testing is the key.

Sometimes it can be worthwhile to do some sampling in the different layers of desert material when they are present and exposed. Gold concentrations in and between flood layers can happen even more in the desert. This is because of the flash floods which can occur there.

Sometimes substantial gold concentrations can be found just beneath boulders which rest upon bedrock, or up in a layer above bedrock.

When you find a gold deposit in a dry area, whether on bedrock or the caliche, you will want to thoroughly clean the underlying surface upon which the gold is resting. Seldom will you visually see gold in dry placer material-even when there is a lot of gold present. Use a whisk broom or vack machine to clean all of the loose material. Sometimes, it is also productive to break up the surface of the caliche or bedrock with a pick or other crevicing tool.

Occasionally, in dry washes, you can actually see stringers of black sand along the bedrock or caliche-especially directly after a storm. You can sometimes do exceptionally well by following these stringers and digging out the concentrated gravel traps. Do not forget to test the roots from trees and other vegetation in such areas. Vegetation requires a certain amount of mineralization to grow. Roots can grow in and around high-grade gold deposits. I have heard of single roots which have been dug up and produced as much as three ounces of gold!

Some electronic prospectors use their metal detectors to trace concentrations of black sand. Then they follow up by testing the areas which produce the strongest reads from their detectors.

Some desert areas, like Quartzsite, Arizona, also have gold just lying around anywhere-even on top of the ground. Such places are excellent for electronic prospecting and dry-washing. The deserts of Australia are famous for this. I have a number of friends who have been very successful in the Nevada deserts, using metal detectors to recover large numbers of nuggets, some very large, directly off the surface of dry desert ground.

If you find a piece of gold on the surface of a dry placer area, it is likely that there are more pieces of gold in the immediate area. Electronic prospectors call these areas “patches.” Gold generally does not travel alone-unless it was dropped there by mistake.

Sand dunes in the desert are usually not very productive. This is because they mainly consist of lighter-weight sands that were deposited there by the wind. However, sometimes the wind can blow off the lighter-weight sands from a particular location, leaving the heavier materials exposed behind. This is similar to what happens after a big storm at the gold beaches. This is something that should be watched for.

When prospecting around in the dry areas, when you encounter tailing piles from past dry-washing operations, it might be worthwhile to do some raking of the tailings and scan around with a metal detector. Sometimes old tailing piles can be productive enough to run them through a modern dry-washer.

 

 

By Jude Colleen Kendrick

 

Dry washing1I remember, in my beginning days of prospecting, driving through the Upper Mojave Desert in Southern California, looking for mines to explore and tailings to scratch through. Occasionally, off to the sides of the road, I would spot small areas where dust and sand billowed up. At first, I thought that they must be “dust devils,” yet they never seemed to change position. In my imagination, I wondered if someone was sending up smoke signals, because that is what they appeared to resemble. One day, I decided to satisfy my curiosity and follow a dirt road up to the puffs of dust.

As I drove up, I saw an old man shoveling gravel into what I now know was a dry-washer. My own previous experience in gold mining had been with suction dredges, so I was excited at the possibility of another way to find gold! The gentleman was kind enough to show me how his dry-washer worked. He explained that he also dredged during the summer. But during the winter months, he headed for the more moderate desert-climates. The thought came to me that now I could prospect year-round, and that everyone in my life would really be annoyed at that. This was because I didn’t leave much time for anything else but gold prospecting, as it was!

For a more comprehensive explanation about dry-washing, please click here.

The old prospector’s machine was a “Nicks Nugget;” which, as I understand it, was constructed upon the design of an “Old Beck’s” dry-washer. It basically worked from a large bellows which was run by a small gas engine set up around 10-feet away (to separate the motor further from the dust). There was a 10-foot leather belt attached to the pulleys. I noticed that the pulleys were connected in such a way that the entire machine vibrated when the bellows opened and closed. The man told me that he would not have any dry-washer other than a Nicks Nugget I, of course, asked him where I could find one for myself. He told me, “Someone one has to die, because they are not made anymore and that’s the only way you’re ever going to buy one!” That is exactly what happened about a year later. An old prospector in the town of Randsburg passed away. I heard that his equipment was being sold and bought the Nicks Nugget!

Drywashing machineMy machine has great recovery. I have tested my tailings throughout the years; and to my knowledge, I have never lost a single speck of gold!

The desert is peaceful and quiet. At night, you can see the sky and stars in a way that is beyond words…

I should point out that dry-washing is a dirty way to prospect. No matter where you set up the machine so that the dust blows away from you, the wind figures out what you are doing. Then it changes direction so that you get a mouth-full of dust with every shovel-full of gravel! I suppose this is just one of Mother Nature’s many ways of making you pay dearly for her most cherished golden treasures!

Most of the time, I wear a bandanna, which helps a little. But when I go back to camp, I still look like “Pig-pen” from the Peanuts cartoons! Still, it has always been worth it.

Winter in the desert can be hard at times, because the temperature-changes are quite drastic. It will be a comfortable 70 or 75 degrees during the day. Then, the afternoon winds can gust up to 60 miles per hour, and the temperature can drop as low as 20-degrees during the night. I woke up one morning to find that all of my panning water was frozen solid. I could not believe it!

The desert also demands the most out of your creativity and imagination. Very often, we all forget some part of our equipment, no matter how careful we are about packing. Yet with a little thought, anything can be fixed. On one trip, I had forgotten my large panning tub, so I ended up digging a hole, lining it with a large plastic garbage bag, holding the edges down with rocks. Presto; a baby swimming pool! I used it to pan down and perform final clean-up on the concentrates from my dry-washer.

Another time, the worst possible items were forgotten; which were the legs to my dry-washer. Can you imagine? I was frantic! After a few moments of figuring my whole trip was for nothing, I looked over the poles from my picnic awning, and the light went on in my head. Shortly thereafter, I took two of the poles, broke them off at the length I needed, and punched four holes in the poles for the nuts and bolts. Within minutes, I was already cranking up the dry-washer. There is always some solution if you are in the right state of mind; you just have to find it! I’m sure this is all just a part of gold prospecting.

The beauty of the desert makes up for any discomforts which you may experience along the way. Usually, nobody is around for miles. It is peaceful and quiet. At night, you can see the sky and stars in a way that is beyond words. And the gold has always been there for me, from flour to nuggets of various sizes and shapes.

One of my favorite things to do while dry-washing is run my machine all day, collect all of the concentrates; and then at night, by lantern-light, pan everything out! There is something wonderful about working everything down to that glimmering, beautiful gold at the end of my day!

During my years of dry-washing, I have spent Christmas out in the desert a number of times. One year, I grabbed three friends (who have parents and family in other states), and took them to one of my mining claims for a “different” type of Christmas celebration. We decided we would cook our turkey on the BBQ and try to make the side dishes on the Coleman stove. A friend of mine had hooked-up an apparatus so that my rotisserie on the BBQ worked off a 12-volt battery. It was great!

My friends and I thought everything was under control until we realized we had bought too large of a turkey. So we ended up eating our Christmas turkey at 10:30 at night! By then, we had already eaten all of the side dishes as “appetizers.” After a few toasts of champagne, nobody seemed to care much about how or when the turkey was done! It was sometime during that evening that one of my friends decided to make a “snowman” out of three large round lava rocks. Even though there was no snow out there, we found ourselves making the best out of our situation. I’m certain that none of us will ever forget that Christmas experience!

Now-back to the important thing — gold! I have usually dry-wash alone; but when I do have a partner, it certainly makes things a bit easier on both of us. One person can be breaking-up the gravel while the other can shovel. During one of my trips, I ran into my friend Ed “Half-Bucket” Daugherty. So we decided to team up for a while. Later, when we realized that we were onto some good gold, he and I were both feverishly shoveling gravel into my machine so fast, that several times we crossed our shovel handles and sent gravel flying everywhere. To this day, I am convinced that it was those lost shovelfuls which had the big nuggets in them! I’ve often wondered if “Half-Bucket” ever went back out there to get them…

I once watched a young man with a whisk broom and dust pan going from one prospect hole to the next, left behind by other people. He merely swept the shelf completely clean and panned-out what he had collected. He found more gold that way than I did running yards of gravel into my dry-washer! So I started using this method, but took it a step further. I took a gas-powered vacuum, sucked up the layers left on the shelves by others, ran that material through my dry-washer, and then panned-down the concentrates. Trust me; by following this method, I have always recovered a lot of color and sometimes a small nugget or two. I nicknamed this method “dry crevicing.”

While I have not tried it yet, I have run across others in the desert who have made fantastic gold recoveries using modern metal detectors to locate pockets and “patches” of nuggets. I have this plan of trying to combine modern electronic detecting with dry-washing…

At the time of this writing, it remains a little warm to start working my mining claims in the desert. Writing about it, though, has me counting the days until the weather cools.

Until then, I’ll look at my gold from last season and imagine my bottles completely full for the next time.

But even if they aren’t full, the desert and dry-washing are wonderful for the winter months. I can’t wait! Good Luck!!

 

 

BY BOB RETHWISH

Learning to Dry-wash Effectively

 

DrywashingI had just driven back to our mining claim seven miles northeast from the town of Quartz site, Arizona. As I stepped into our travel trailer, I warned my wife, Norma, “Don’t look into the back of the truck.” Of course, she immediately looked out the dining room window and said, “I don’t see anything.”

I sat down at our small kitchen table and explained, “You don’t see anything because I covered it with that old army blanket. Now promise me you won’t go out and…” She jumped up from reading her cookbook and dashed for the door. Being closer than I was, she escaped easily. By the time I got to the door, she was throwing the blanket back.

I hollered to no avail, “Tomorrow’s your birthday!” Without looking at me, Norma said, “So… ?” And then she screamed, “A drywasher! Let’s go try it out.” When I reached the truck I said, “Let’s at least wait ’til after lunch.” She was running around grabbing shovels and buckets and said, “I’m not hungry.” God knows that wasn’t true–she’s always hungry!

Our love for gold began in the early 1980’s when I got Norma an inexpensive White’s metal detector for Christmas. Traditionally we open one present on Christmas Eve; and she, by chance, unwrapped her metal detector. When I went to bed hours later, Norma still had all her unwrapped presents spread over the playroom floor and she was busy checking each one with the detector. As I drifted off, I heard the detector sound off once again and Norma mutter, “Aha!” and, “I know what that is,” and “Hmmm.”

From that seemingly innocent Christmas gift, our lives changed dramatically.

Originally, after spending a summer dredging, we traveled to Quartzsite, Arizona to sell our gold and gold jewelry at swap meets on the weekends. This normally inconspicuous little town with RV parks and BLM open desert camping, just east of the California border on Interstate 10, balloons from a few thousand permanent residents to well over half a million people during the winter! It has a real circus atmosphere, the main attraction being the rock and mineral displays at a multitude of swap meets and shows. In the midst of all this are airplane rides, balloon and buggy rides, side shows, live music, antique sales, and perhaps a little junk. And let’s not forget the food vendors, guaranteed to satisfy any craving (except Norma’s). We came to sell our gold, we saw what was going on, and we stayed.

Shortly thereafter, we claimed 20 acres in the foothills, seven miles south-west of town. That was14 years ago. This is where we still dry-camp and dry-wash for gold during the winter months. It’s R and R (rest and relaxation).

Our first dry-washer was gas-powered and larger than I cared for. It did a great job, but after dredging all summer, I needed a reprieve from hard physical work. After all, I was in my fifties.

Remember that classic Lucille Ball routine where she and Ethel Mertz worked on a conveyor belt packing chocolates, and couldn’t keep up? That’s how I felt with that large dry-washer. One day, right after dry-washing, I was sitting in our truck, exhausted. I started the truck and I remember Norma hollering, “Stop! You’re going to run right over the dry-washer!” I think I was subconsciously trying to destroy it. “Let’s sell it,” Norma said, “while we still have one to sell.” We traded it for a gold spinner the next day.

It was a few years later when I bought the inexpensive, hand-operated dry-washer, which brings me back to Norma pulling the blanket off of it.

We went out that first day and truly enjoyed ourselves. As we headed for the wash, Norma said, “Remember all those characters who came out here years ago to dry-wash? I’ve been thinking about all the things they did and said that I didn’t pay much attention to at the time. I forget his name, but there was that older guy that came out on a motorbike with his dry-washer and his bucket, shovel, and lunch box all strapped to him and his motorbike. You know who I mean. Well, he said to find an area in the wash where the caliche (a desert hardpan, almost like cement or bedrock) took a dip and formed a basin where the gold would settle. I remember him so vividly. I was always amazed when I saw him on that little motorbike with only his eyes showing.”

We arrived at the wash and Norma said, “I’ll show you what he was talking about.” She found a low spot in the overburden and continued, “Like right here.”

I agreed and said, “Well, let’s try it.” Norma, however, was still looking things over and she warned, “I remember he also said to keep in mind where the origin of the gold might be and which side of the wash could have been an old river bed, and to get close to both”

While she was looking around, I went back to our truck, which was parked nearby, and picked up the dry-washer. When I arrived back at the wash, I asked her where she thought we should start. She pointed with the shovel and said, “The mountains are there. That would be the origin, and I checked that bank and it looks like an old river bed.” She motioned to a spot and added, “I think that’s a good spot.”

So we started and took turns operating the handle and shoveling into the dry-washer. The person pumping the handle sat on an upside-down 5-gallon bucket, and took in the scenery; it was a cushy job.

After a while, I got up from the bucket and told Norma, “I know you’re not hungry, but I’m going to walk up that rise and have lunch.” “Go ahead, I’ll keep going for awhile,” Norma answered. “Aw heck, if you’re going to eat, I might as well eat, too.” We climbed up and found a comfortable rock in the warm sun. Directly behind us were the Dome Rock Mountains, but toward the east we had a panoramic view of the Kofa mountains, maybe 20 miles away. We could also see our trailer bordering a small hill that we had named ” Almost hill.”

Norma drywashingAfter a few bites of her sandwich, Norma pointed and said, “That looks like jade.” She slid down about 15 feet and knelt to dig, the best she could do with a sandwich in one hand. She stood up to talk to me and spooked a doe, which immediately bounded away, leaving a yearling frozen in its tracks. The doe turned and squealed. The baby bounded down the hill awkwardly, and they happily reunited. It was an unequaled thrill.

Norma shovels into the dry-washer–

We finished lunch and continued dry-washing. When we reached the caliche, Norma told me a guy with a red scraggly beard had told her to take a lot of time brushing the hard surface, making sure it was absolutely clean, as the gold stops there. He did find more gold than most, so we decided to give the caliche a good cleaning. We put the “brushings” thr through the dry-washer and decided to clean-up. We had dry-washed for only an hour, but were anxious to see how we were doing.

Norma carefully removed the sluice and transferred the concentrates to the bucket we had been sitting on. We returned to our trailer and she started panning into a shallow tub filled with water. As I unloaded the truck, I heard Norma casually say in a sing-song voice, “You won’t believe what I just found.”

I walked to her and there it was–a beautiful, bright gold nugget, contrasted against the green gold pan. It was jagged and rough, not river-worn like we were accustomed to.

Norma tilted the pan toward me and said to start backing up. She told me to back up until I couldn’t see the gold nugget, and then to take a step forward. When I was a good distance away, I hollered to Norma that I couldn’t see it, then I took a step forward to where I could just barely see the nugget. Norma put the pan and nugget on the ground at her feet and said “Stay right there.” She got a carpenter’s tape and measured the distance between me and the nugget. It was 49 feet, exactly. We named it our “49’er nugget.”

As we finished panning, it began to rain. We knew we couldn’t dry-wash when the ground was wet, so we grabbed a plastic tarp, drove out to the claim, and covered the area where we had found the nugget. It takes a lot of rain to really soak up an area, so a tarp usually does the job.

Reflecting back on those first years with our dry-washer, we also followed a tip from a guy called “The Professor,” and started taking a tub and water out to the claim with us so we could pan out on site. We’d dry-wash, have a picnic, and pan right there. Life doesn’t get any better than that!

Another guy, a skinny, suntanned nudist who sometimes wore a dress (really!), had a 10-foot extension to his dry-washer sluice. I personally don’t think it was worth the trouble. That guy did have one good idea, however. When he changed locations, he always cleaned his sluice, so he would know how much gold came from each location. He called it “proper sampling technique.”

What this is all leading to is that we’ve learned by watching, listening, and then doing. Just go do it. Those who have the right approach certainly do seem to recover more gold and make the exciting strikes! You’ll have fun and the gold you get will be a bonus!

Well, Norma is looking out our trailer window towards our mining area.

Excuse me, but I have to fix some sandwiches.


 
Dave Mack

“You can also find gold out in the deserts and other dry areas where there is little or no water available.”